164
FXUS62 KJAX 261119
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
719 AM EDT Sat Jul 26 2025

...New AVIATION...

.SYNOPSIS...
Issued at 332 AM EDT Sat Jul 26 2025

Overnight surface analysis depicts high pressure (1021 millibars)
centered directly over our region. Aloft..."Heat Wave" ridging was
positioned over eastern portions of the Carolinas and southeastern
GA. Latest GOES-East derived Total Precipitable Water imagery
indicates that PWATs have fallen below late July climatology for
our area, with values generally in the 1.5 - 1.75 inch range. Even
lower moisture values were located to the south of Interstate 4 in
the FL peninsula, where values have fallen to the 1.25 - 1.5 inch
range. Fair skies prevail area-wide, and decoupling winds at
inland locations have allowed temperatures at 07Z to generally
fall to the 75-80 degree range, with dewpoints mostly in the low
to mid 70s.

&&

.NEAR TERM...
(Today and Tonight)
Issued at 332 AM EDT Sat Jul 26 2025

Stacked ridging will become centered over southeast GA this
afternoon and evening. Strong subsidence will limit convective
potential for locations from Waycross northward. Meanwhile, PWAT
values for areas south of Waycross are expected to rise slightly
back towards climatology (1.7 - 1.9 inches) this afternoon, which
may be just enough to develop isolated to widely scattered
convection this afternoon, mainly for inland locations along and
south of the Interstate 10 corridor. This activity would be
triggered by the inland moving Gulf and Atlantic sea breeze
boundaries, in addition to other mesoscale boundaries such as the
Lake George and St. Johns River breezes, with these boundaries
likely colliding near the U.S. Highway 301 and/or 17 corridors
late this afternoon. Strengthening subsidence will likely result
in transient convection that will likely remain brief in nature,
with strong storms unlikely. The bigger story today will be the
heat, with plenty of sunshine and subsidence allowing highs to
soar to the upper 90s at most inland locations, while coastal
locations rise to the low and mid 90s before onshore winds in the
wake of the inland moving sea breeze drop temperatures back to the
upper 80s to around 90 by late afternoon. Forecasting dewpoint
temperatures today will be tricky due to increasing subsidence
that may be offset by inland moving sea, lake, and river breezes.
Decided to trend values slightly above blended guidance for the
late morning and afternoon hours, which yields heat index values
mostly in the 105-110 degree range across our area. We maintained
the Heat Advisory for all but the interior southeast GA counties
to the west of Baxley, Alma, and Waycross, where peak heat indices
should remain closer to 105 degrees.

Fair skies should again prevail for the majority of the evening
and overnight hours tonight, with any convection that manages to
develop this afternoon likely dissipating towards or shortly after
sunset. Surface winds will decouple at inland locations towards
midnight, resulting in lows falling to the mid 70s again at most
inland locations. A light southwesterly breeze at coastal
locations will keep lows in the upper 70s to around 80 around
sunrise on Sunday.

&&

.SHORT TERM...
(Sunday through Monday night)
Issued at 332 AM EDT Sat Jul 26 2025

Stacked high pressure overhead on Sunday gradually shifts west-
northwestward on Monday bringing dangerous and potentially record
heat to the area. On Sunday, strong subsidence and lower PWATs
(1.4 - 1.7 in) will continue limited convective coverage with
mainly isolated showers and storms developing over inland NE FL as
the sea breezes shift inland. High temperatures soar to near
record ranging in the mid 90s along the coast to the upper 90s to
around 100 F inland. Area-wide Heat Advisories are likely on
Sunday with peak heat indices in the 107-112 F range. On Monday,
an influx of moisture and departing subsidence will bring a return
of isolated to widely scattered showers and storms developing
along the sea breezes. Despite an increase in storm coverage,
Monday is on tap to be the hottest day of the summer with record-
breaking highs in the upper 90s to low 100s and peak heat indices
potentially peaking in Extreme Heat Warning criteria (heat index
113+ F) for much of the area. There won`t be much relief overnight
as lows will only "cool" into the mid/upper 70s to around 80.
With dangerous heat expected, it is important to refrain from
extended periods outside during the afternoon hours and remain
hydrated to avoid heat-related illness.

&&

.LONG TERM...
(Tuesday through Friday)
Issued at 332 AM EDT Sat Jul 26 2025

Dangerous heat continues through mid-week with a moist airmass and
near record temperatures. An upper disturbance passes through the
region Tuesday into Wednesday increasing convective coverage to
scattered/numerous. Atlantic high pressure ridging builds back
across the FL peninsula Thursday into Friday bringing a return to
a more typical afternoon summertime pattern of sea-breeze driven
convection. Temperatures adjust down by a couple of degrees with
highs in the mid to late 90s but lingering moisture will maintain
peak heat indices in Heat advisory criteria (108-112 F).

&&

.AVIATION...(12Z TAFS)

Unusually dry airmass lifting across the region this morning
combined with suppression from a strengthening ridge of high
pressure will lead to VFR, sea breeze dominant wind patterns, and
isolated showers and thunderstorms today. Given the very isolated
nature of convection the TAFs have been limited to vicinity
mentions at this time but updates may be needed as showers attempt
to develop later today. Quiet conditions tonight and a near
repeat of today`s weather trends again Sunday.


&&

.MARINE...
Issued at 332 AM EDT Sat Jul 26 2025

High pressure centered over our local waters today will shift
westward tonight and Sunday, allowing a trough to develop over
the southeastern states that will settle over our area early next
week. Dry weather will prevail this weekend, with chances for
showers and thunderstorms gradually increasing next week as
troughing begins to shift to the west of our local waters by
midweek and Atlantic high pressure builds westward towards the
Florida peninsula on Thursday and Friday. Seas of 2 to 3 feet will
prevail both near shore and offshore during the next several days.

Rip Currents: Developing onshore winds during the afternoon hours
will combine with a persistent easterly ocean swell to create a
lower end moderate rip current risk at all area beaches this
weekend.

&&

.FIRE WEATHER...
Issued at 332 AM EDT Sat Jul 26 2025

Light northwesterly surface and transport winds developing shortly
after sunrise will shift to westerly this afternoon for locations
north of Interstate 10 and southwesterly for locations south of
I-10. Light speeds today will result in poor daytime dispersion
values for inland locations south of I-10 and also at coastal
locations, where breezy onshore surface winds will develop early
this afternoon. Elevated mixing heights across inland southeast GA
will yield fair daytime dispersion values. North-northwesterly
surface and transport winds on Sunday morning will shift to
northerly during the afternoon hours for inland locations south of
I-10, while onshore surface winds again develop at coastal
locations early in the afternoon. Elevated mixing heights will
yield good daytime dispersion values at all inland locations on
Sunday and Monday afternoons. Northwesterly surface and transport
winds will prevail for inland portions of southeast GA on Monday,
while northerly winds elsewhere shift to northeasterly during the
afternoon hours. A very hot and unseasonably dry air mass will
result in minimum relative humidity values falling to around 35
percent on Monday afternoon across inland southeast GA and
northern portions of the Suwannee Valley.

&&

.CLIMATE...
Issued at 333 AM EDT Fri Jul 25 2025

Daily Record High Temperatures at our local climate sites...

                     SAT 7/26   SUN 7/27   MON 7/28   TUE 7/29

Jacksonville, FL     102/1872   100/1872   104/1872   100/1875
Gainesville, FL      100/1952   101/1893   97/2010    99/1896
Craig Airport, FL    97/2012    99/2010    98/2016    101/2016
Alma, GA (AMG)       101/2012   99/2014    100/2006   99/2016

Daily Record High Minimum Temps at our local climate sites...

                     SAT 7/26   SUN 7/27   MON 7/28   TUE 7/29

Jacksonville, FL     86/1872    85/1872    80/1885    80/1877
Gainesville, FL      78/2018    77/2010    77/2014    77/1899
Craig Airport, FL    79/2015    80/2010    80/2014    79/2017
Alma, GA (AMG)       77/2010    77/2018    78/2014    77/2017

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  98  76  99  77 /  10   0  10   0
SSI  95  81  96  82 /   0   0  10   0
JAX  98  78  99  78 /  20   0  10   0
SGJ  93  78  94  79 /  20   0  10   0
GNV  97  76  99  78 /  40  10  20   0
OCF  95  76  97  77 /  30  10  30  10

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Heat Advisory from 11 AM this morning to 7 PM EDT this evening
     for FLZ021-023-024-030-031-035-038-120-124-125-132-136>138-
     140-220-225-232-233-236-237-240-322-325-333-340-422-425-433-
     522-533-633.

GA...Heat Advisory from 11 AM this morning to 7 PM EDT this evening
     for GAZ134>136-151>154-162-163-165-166-250-264-350-364.

AM...None.
&&

$$